Ducati 250cc Mach1

Hi I wonder if anyone can help.
I’ve acquired a 250 Mach 1 basket case.
Mach 1 engine and frame numbers a correct to the old beige log book the one with the past owners with the original registration.
Last registered keeper was in the early 70s I believe It was raced back in the day so no further registrations I have enough parts minus the tank and side tool boxes to put it back as a road bike.
So my question is do I need to show a complete bike which may take me a year or so or can I send for a V5 with just the engine and frame.

Thanks in advance for any advice
Side note if anyone has parts to complete the build please get in touch. Mbianchi@hotmail.Co.uk